Rotovolumetrical pump



Dec. 20, 1955 A, DUTREY ROTOVOLUMETRICAL PUMP 4 Sheets-Sheet 1 Filed May 23, 1951 m viii/*6.

Dec. 20, 1955 A. DUTREY ROTOVOLUMETRICAL PUMP 4 Sheets-Sheet 2 Filed May 23, 1951 United States Patent ROTOVOLUMETRICAL PUMP Andr Dutrey, Paris, France, assignor to Socit Nouvelle des Etablissements Brandt, Paris, France, a corporatlon of France Application May 23, 1951, Serial No. 227,847

Claims priority, application France May 27, 1950 Claims. (Cl. 103-4) The present invention relates to volumetric pumps, and more particularly to pumps of the type including a hollow spherical casing into which two shafts extend' at a constant angle with respect to each other, one of these shafts rotating freely on its own axis, the other being driven, each of these shafts being made integral with a part spherical member revolving within the spherical easing, and these two members being movably connected, by a Cardan or like universal joint formed by two trunnions perpendicular to each other, with a third intermediate part spherical member.

The assembly of these three part-spherical members constituting the rotor of the pump, does not form acornplete sphere, mitres being provided between them in order to permit the intermediate member to rock between each of the outer members by varying the width of the mitres. Each of the four mitres thus formed constitutes an intake and discharge chamber the volume of which varies during each revolution of the driving shaft, and passes over either of the two openings provided in the spherical casing, constituting the inlet and discharge openings respectively, depending on the direction of rotation. It is thus possible to construct a twin pump occupying a very small volume.

The mechanical realization of these pumps poses very arduous practical problems, namely in the design of the two perpendicular trunnions of the Cardan, which must pivot freely about their own planes and independently from each other, all this with an absolute tightness between the four mitres.

The object of the present invention is to provide means leading to the solution of this problem with a good safety margin and being at the same time very economical, by the utilization of elastic material members such as rubber for instance, made integral with the different shafts to be coupled and co-acting with a central member with which they can eventually also be made integral.

According to one particular embodiment, the three part-spherical members are rigidly connected with a common spherical block made of elastic material out of which they have been cut, the variable width mitres being constituted by the cut out parts, the relative oscillating movements of the three members being obtained by an elastic deformation of this spherical block.

Another improvement brought by the present invention resides in the arrnouring of the deformable rubber core by adding a canvas or metal armour to the zones exposed to the greatest strain as regards compression, distension and torsion under the action of the driving torque.

Finally a last improvement consists in grouping a set of pumps all the rotors of which form a single unit entirely made of elastic material, revolving in a common casing, the different elements of this unit being eventually, according to the needs, coupled either in series or in parallel, the rotor being eventually driven by two synchronised electric motors coupled at each end of the shaft.

Figs. 1 to 4 recall as a reference the known principle according to the invention, Figs. 1 and 3 representing 2 the pump in two operating positions, and Figs. 2 and :4 showing the different constituting members of the pump.

Fig. 5 which relates to the first embodiment of the invention, is a cross-section'taken along line V-V in Fig. l, of the central part-spherical member supporting the Car dan coupling trunnions.

Fig. 6 shows a similar cross-section of. a first modification of the invention.

Fig. 7 is a perspective view of the rotor assembly in a second modification.

Fig. 8 is an elevational view of a solid rubber spherical assembly from which the three part-spherical members have been cut.

Fig. 9 is a plane view of a group of pumps mounted in series.

Fig. 10 is a cross section along line XX in Fig. 9.

Fig. 11 shows the same, assembly mounted in parallel.

The pump illustrated in Figs. 1 to 4, of the usual known type, is constituted by a spherical casing in which are fitted two bearings 2 and 3 supporting two shafts 4 and 5 the axes of which make a constant angle a with each other, one of the shafts, for example the shaft 4, being driven and the shaft 5 beingfree in its bearing 3. The two shafts 4 and 5 are each rigidly connected with one of two part-spherical members 6 and 7 respectively, fitting by their outer surface against the inner wall of the casing 1 and independently coupled with a common intermediate central part-spherical member 8. This double coupling is realized by means of two trunnions 9 and 10 set at right angles to each other pivoting about their own axes in the core of the intermediate piece 8.

The three members 6, 7, 8 do not occupy the entire space within the spherical chamber of the casing, part spherical mitres 11, 11, 12,12 being reserved between them, the width of these mitres being at least four times as great as the angle a between the axes X-X and Y--Y formed between the shafts 4 and 5.

As it will be observedon the drawings, namely upon comparing Figs. 1 and 3, therotation of the shaft 4 will cause simultaneously the spherical assembly 6, 7, 8 to pivot about the shaft 4 and a relative oscillating move ment of the member 8 towards the members 6 and 7 by varying the width of the mitres 11, 11, 12, 12.

Finally, two openings 13 and two openings 14 are provided in the casing, the drawing showing only one of the two openings coacting with the mitres 11, 11', 12, 12' respectively and constituting the inlet and discharge passages respectively, depending upon the direction of rota tion of the driving shaft. I

The problem which it is proposed to solve according to the invention consists in ensuring the tightness of each one of the chambers 11, 11, 12, 12' with respect to the others while at the same time permitting the oscillating movement of the two trunnions 9 and 10.

According to a first embodiment represented in Fig.- 5, the two trunnions 9 and 10 have been divided into two half-members 9 and 9a, 10 and 10a, supported by a ball 15 arranged in the core of the member 8 which, it should be mentioned, is the center of the sphere, the members 6 and 7 bearing on this sphere 15. It is at once apparent that this arrangement permits the different movements which have been described above. A fitting 16, made of elastic material, such as rubber for instance, provided at the end of each of the six memberssupported by the sphere, ensures the tightness between the moving parts and the ball, permitting the movements and making up for the wear of the pieces in contact.

The fitting for the outer members 6 and 7 may be directly fitted on the end of the members without the shafts 4 and 5 extending necessarily to the center of the ball. The bearing surfaces of these elastic cross-pieces have been represented in 16' and 16".and. are offset y,

a value depending on the angle a.

The location of these bearing surfaces has been shown in Figs; 2 and 4 to make'the drawing more explicit. It will be noted that according to a similar but inverse arrangement, the trunnions could be made of metal and be supported by a central spherical core 15 made of elas tic material.

In the embodiment shown in Fig. 6, the central metal ball 15 is replaced by a core 15a made of elastic material and cast in one piece with the elastic masses 16, 16', 16" mounted on the ends of the four trunnions 99a. and 10--10a, and on the shafts 4 and 5 passing through the thicker part of members 6 and 7. The friction between the elasticsurfaces 16, 16', 16" and the central piece is then replaced by an elastic deformation of theextensiohs 16, 16, 16 with respect to the core 15a.

Fig. 7 shows another modification in which the core 15a is constituted by the member 8 itself made of elastic material, the members 6 and 7 having their center parts integrally joined to the intermediate member 8-forming the central core.

In normal operation the elastic member 8 can be provided with a metal shell 17 serving as a medium in the friction fitting against the inner surface of the casing 1. This shell 17 can also eventually constitute a form for the molding of the member 8 and its assembly-with the metal'members 6 and 7.

In the embodiment illustrated in Fig. 8 the three members 6, 7, 8, arecut out of a single spherical rubber block and parts have been cut to form mitres.

The opening and the closing of these mitres caused by the rotation of the driving shaft 4 will cause a deformation of the rubber. Metal members 18, 18', embedded in the material stiffening the rotor will limit the degree of deformation. The rotor can also be reinforced with canvas over all or part of its surface. Either metal or canvas elements 19 can also be provided as a protection against the torsional stresses to which they are exposed, caused by the rotation of the shafts 4 and'5;

Finally these three members may also as shown in Fig. 7', be enclosed ina metal shell through which takes place the sliding action against the inner surface of the casing.

According to another characteristic of the invention illustrated in Figs. 9 to 11, the pump comprises a multiple rotor enclosed in a common casing formed by two shellha'lves 20 and-20 mounted in a common diametral plane, and constituted by a series of primary bloc-ks A, B, C; D,

Each of these blocks include the above described membars 6,. 7, 8; the outer ends of two successive blocks are mounted in a sti'aight' line by means of cylindrical ele ments E, the last element of the outer blocks A and-D is connected to the shafts! and 5 through cylindrical end elements E; The assembly A, B, G, D, E, E is molded or cast in one piece and the common isprovided with spherical pair's connectedin airs by cylindrical parts Ea set at an angle awith respect to each other; corresponding to the angle of operation as above defined. Owing-to this arrangement,- when the group is composed er an even number of elements, the two outer elements E are parallel, and it is possible to drive simultaneously the two outer shafts '4 and 5 by two synchronized electric ntmtors 1 It will also be remarked that-the transmission ofpower from oneelement. to the next will be vgreatly helped by reinforcing, the cylindrical intermediate, elements E with canvas so arranged so that the canvas fib rs resist f action.-

The multiple pump constructed in this manner can be mounted in various manners, depending whether an in: crease in pressure or an increase in output is required. In Big, 9 for instance th'e'punip comprises an inlet tube grcennectea tothe first element and one discharg" '22 connected to the last, th vario s elements being 'eo nested in' series by intermediate tubes 23' connecting the aisensrgs'of one terns inlet "of-the other:

On the contrary, Fig, 11, the inlet tubes. of, allrthe pumps are connected to a common tube 21 and the indi vidual discharge tubes 22 are also connected to a common tube 22'.

What I claim is:

l. A volumetric pump comprising a hollow spherical casing having an inlet and an outlet, two shafts at least one of which is driven, extending into said casing in angularrelation to each other and each having'a' part: spherical member integral therewith and a thiidiilkrmediate part-spherical member hingedly connected to the first two part-spherical members, the sizes of said three part-spherical members being such as to leave between two consecutive part-spherical members two mitres defining two chambers the volume of which varies during each revolution of the driven shaft, said inlet and said outlet being located to communicate respectively with said chambers and universal joint means of elastic deformable nature connecting respectively said first and said second members to said third member whereby asnug fit is pievided between said members and said casing and said chambers are separated from each other in fluid-tight manner.

2. A pump according to claim 1 wherein said universal joint means comprise a ball located concentrically with said three members, two pairs of aligned trunnions and elastic connection means between said ball and said trunnions, the trunnions of said one pair extending perpendicularly to the trunnions of said second pair,- each pair respectively connecting one of said two first men tioned members to said third member.

3. A pump according to claim 2 wherein said ball'is made of elastic material. -f

4. A'pump according to claim 3 wherein saidball is integral with said trunnions.

5. A volumetric pump comprising a hollow spherical casing having an inlet and an outlet, two shafts at least one of which is driven, extending into said casing in angu lar relation to each other and each having a part-spheri= cal member integral therewith and a third intermediate part-spherical member hingedly connected-to the first two part-spherical members, the sizes of said three partspherical members being such as to leave between two consecutive part-spherical members two mitres defining two chambers the volume of which varies during each revolution of the driven shaft, said third part-spherical member being made of elastic material, whereby said inlet and said outlet being located to communicate respectively withsaid chambers, and universal joint means of elastic deformable nature connecting respectively said first and said second members to said third member, whereby a snug fit is provided between said members and said casing and said chambers are separated from each other in fluid-tight manner.

6. A pump according to claim 5, in which the rubber part-spherical intermediate member is enclosed in ametal shell through the mediumof which it is in contact with the inner surface of the spherical casing. F

7. A pump according to claim 1 wherein said thre part-spherical members are made of elastic material and in which said universal joint means are provided by integral connection respectively between said two first mentioned members and said third member, said connections extending respectively substantially along two mutually substantially perpendicular axes of the sphere defined by. said three members, i

8. A system comprising a plurality of pumps according to claim 1 wherein said inlets and outlets of the respec? tive casings are connected in series and wherein said driven shaft of one pumpis rigidly connected with the driving shaft of an adjacent pump.

9'. A system comprising a plurality of pumpsacc'orcling to claim 1 wherein said inlets and said outlets'are respectively connected in parallel to inlet and outlet mani folds and wherein said driven shaft of me pump is ri'g'id 1y connected with the driving shaft of an adjacent pump.

10. In a volumetric pump of the type comprising a hollow spherical casing, two part-spherical members located inside said casing and a third part-spherical member defining with the two first said part-spherical members respectively two chambers communicating with the outside and changing their volume as said two members are rotated: universal joint means of elastic deformable nature connecting respectively said two part-spherical members and said third part-spherical member whereby an exact fitting is provided between said members and said casing and said chambers are made fluid tight with respect to each other.

References Cited in the file of this patent UNITED STATES PATENTS Kirby July 27, Kearney July 24, Kempthorne Oct. 8, Holmes Aug. 4, Jensen June 18, Dutrey Mar. 28,

FGREIGN PATENTS Great Britain July 10, 

